Ironman Finish Time Predictor
Predict your full Ironman finish time from your real FTP, swim CSS, and run threshold pace. Free, no signup, no email gate.
These are model-based estimates, not guarantees. Race day depends on heat, fueling, pacing discipline, and luck. Treat the number as a planning target, not a promise.
Your current fitness
Your estimated finish
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TriPaced builds an adaptive long-course plan around your real thresholds and recalibrates as you train. The beta is open — we review every application by hand.
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How the prediction works
- Swim: your CSS pace slowed by 5% for open-water Ironman fatigue, over 3.8 km.
- Bike: 72% of FTP (course-adjusted) converted to road speed with an open aero + rolling-resistance power model, over 180 km.
- Run: your threshold pace slowed by an Ironman fatigue factor (11–16% depending on experience), over 42.2 km.
- Wall risk: we flag the over-bike profile — strong legs (≥3.6 W/kg) paired with a run threshold slower than 4:45/km, the imbalance that most often forces marathon walk breaks.
Sources: Joe Friel (Training Bible) finish-time framework, Best Bike Split / Martin et al. open cycling power model, Skiba GOVSS run pacing.
FAQ
How does the course profile change the result?
A hilly course (Nice, Lanzarote) costs you both sustainable power efficiency and average speed for the same watts, so your bike and total times go up versus a flat course (Barcelona, Florida). We apply a preset efficiency and speed coefficient per profile.
What is the wall risk flag based on?
It triggers on the over-bike profile: strong bike legs (≥3.6 W/kg) paired with a comparatively slow run threshold (slower than 4:45/km). That combination — a big engine on the bike with less run durability under it — is what most often forces glycogen depletion and walk breaks on the marathon. The model already paces your bike at a sustainable 0.72 IF, so it is the strength imbalance, not raw intensity, that we flag. It is a pacing warning, not a verdict.
Why does W/kg matter for an Ironman?
W/kg sets how fast a given FTP turns into bike speed, especially on climbs. But for a flat Ironman, raw watts and aerodynamics matter more than W/kg. We use absolute power for speed and show W/kg as context.
How accurate is this Ironman finish time prediction?
It is a model-based estimate, typically within 15 to 25 minutes of a well-paced, well-fueled race for an athlete with accurate inputs. Heat, nutrition mistakes, mechanicals, and poor pacing can move it by an hour or more. Use it to set a realistic target, not as a guarantee.
Where do I get my CSS, FTP, and run threshold?
CSS comes from a 400m + 200m swim time trial. FTP comes from a 20-minute bike test (multiplied by 0.95) or your power meter's estimate. Run threshold pace is roughly your fastest sustainable 10K to half-marathon race pace.
Does this replace a coach or a structured plan?
No. It predicts an outcome from your current fitness. It does not tell you how to get fitter or how to pace and fuel on the day. That is what a structured long-course plan like TriPaced is for.